I just got a screaming deal on a 2 GB mini SD card with an SD adapter ($5 on WOOT.com!), and I got it with the express purpose of leaving it in my built-in card reader in my Desktop, and having my TigerPup partition on it.

Here is what is happening: I have Tiger on a 4GB Microdrive (living in another bay of the same reader), and I wanted to move it to the new 2gb card so I could just leave it in, and access Tiger from the boot menu. When I installed it to the CF card, I did a full install, installed Grub to the root of the drive, and when I select the Microdrive (CF card), in the boot options, it boots fine.

When I tried to install Tiger from a remaster I made of my current config, it saw the SD card, but would not mount it. It appeared in Pmount, but there was no option to mount it. I was able to install Puppy Dingo to it (it saw and could mount the card), and Grub to the root, and used Gparted to enable the boot flag.
I thought all would be well, but it just will not boot from the card. I am going to reboot after I post this, and follow up with the exact error message so it will narrow things down.

Firstly, the best place for TigerPup issues is the TigerPup forum... lots of people who use TigerPup regularly check there, and you're probably more likely to find help. I only happened to find your post browsing the new ones, where if you post in TigerPup I'll get an email saying a new post has arrived.

Have you managed to install TigerPup to the SD card? A couple possibilites. With Puppy 3.01 (which TigerPup is currently based on), sometimes there is confusion when using an external SD card if you select the CF option (either of them) when installing from the Puppy Universal Installer. USB flash works much better, and you will have the advantage of being in Pupmode13 (which writes only once every 30 minutes or so). Technically Puppy should recognize a CF device as also needing pupmode13, but it doesn't. This is something I hope to fix with future releases.

Anyway, there should be an empty file with your boot files labeled something like "ideflash", etc. Change it to "usbflash", and in your kernel line in menu.lst for grub, set "pmedia=usbflash".

Which puppy are you using to install to the SD card, if you haven't gotten TigerPup on there yet? Still a bit confused, and need more info. Cheers matey,
~dinky